Objectives Core B, the electrophysiology and computational core, will develop standard methods for processing and analysis of EEG data from both human and non-human primate studies that can be used to identify mirror neuron system (MNS) activity. Both standard nonparametric spectral estimation methods and more recent methods based on parametric modeling, wavelet analysis, and independent component analysis of brain activity will be used to identify mu like responses in infants, children and adults and in the non-human primate studies. Moreover, cortical source analysis will also provide a window to the generators of the mu activity as described below. This core will provide foundational support to each of the Projects for collecfing electrophysiological data examining the mirror system during observafion and performance of action in human infants (Projects I and II), human children (Project I and IV) and human adults (Projects I and IV) as well as non-human primate infants (Projects I and III) and non-human primate adults (Project III).